Stop!
If you buy a TV with a external transformer it is most likely a 12 volt in disguise.
The giveaway is the puck like device on the power cord that looks very similar to a laptop cord.
Read the voltage on the transformer dollars to donuts is will be 12 volt out.
Just buy a cord.
The last I knew the insignia brand at Best Buy and the Sceptre brand at Walmart are both 12 volt in disguise.
All you would need to buy is a 12 volt cord and plug it direct to TV
I have 2, 19 inch TV's one Insignia and one Sceptre that are both 12 volt in disguise